This Application is related to an Application entitled, xe2x80x9cA Universal Telephone Station for Telephone Roamersxe2x80x9d by the inventors of this Application, being assigned to the same assignee and being filed concurrently.
This invention relates to the provision of roaming telecommunications service.
Roaming wireless cellular telecommunications service is a very popular and widely used service. It allows users to take a cellular telephone and originate calls from that telephone even when they are far away from their home location. An elaborate infrastructure has been created which makes this kind of service possible. It includes the provision of a Home Location Register (HLR) associated with a Main Station (MS), a user""s home Mobile Switching Center (MSC), and a Visitor Location Register (VLR) associated with an MSC serving the customer, when the customer is outside the serving area of the home MSC. When a customer registers in a remote MSC, a VLR is assigned to that customer, and the HLR of the customer is informed of this assignment and the identity of the VLR. Calls to the roaming MS are routed initially to the home MSC, which upon consulting its HLR and the VLR for the called MS, routes the call to the remote MSC now serving the MS.
A problem with the prior art is that, while this arrangement is satisfactory for wireless stations, it does not solve the problems of providing incoming and outgoing service to customers who prefer to use wire-line service because, in general, it is much less expensive while away from their home wire-line switch, or because they are in an area where radio signals are too weak.
Applicants have further analyzed the various problems that are associated with providing roamer-like service to land-line customers. In accordance with their invention, a Universal Main Station (UMS) is provided capable of operating as a wireless station, but also capable of being plugged into a jack connected via local loop to a wire-line switch, and thereby operating as a wire-line Main Station; when such a UMS is plugged into a jack other than the home jack of that UMS, a connection is established to a server, which receives a mobile identification number transmitted by the UMS. If the directory number of the owner of the jack is not automatically forwarded via an Incoming Calling Line Identifier (ICLID) message, then the user of the UMS is prompted by the server to provide that directory number. The server then informs the home land-line switch that all calls to the directory number of the UMS are to be forwarded to the directory number of the owner of the jack into which the UMS has been plugged. When a UMS is unplugged from a jack, it automatically becomes a wireless MS, and automatically registers in the manner well known for cellular systems. The UMS in addition to having a land-line directory number, also has a secret cellular directory number, and all incoming calls to the UMS, while that station is in the wireless mode are automatically transmitted initially to the home land-line switch, and then forwarded to whichever cellular switch is presently serving the UMS, the forwarding being done using the secret telephone number of the UMS acting as a wireless station. Advantageously, this arrangement allows a single Main Station to be used alternately as a wire-line station or a wireless station, and allows that station to plug into any jack in the land-line Public Switched Telephone Network (PSTN), and be reachable at that location.